express-http-proxy

Express proxy middleware to forward request to another host and pass response back

Install

$ npm install express-http-proxy --save

Usage

proxy(host, options);

To proxy URLS starting with '/proxy' to the host 'www.google.com':

var proxy = require('express-http-proxy');

var app = require('express')();

app.use('/proxy', proxy('www.google.com'));

Options

forwardPath

The forwardPath option allows you to modify the path prior to proxying the request.

var proxy = require('express-http-proxy');

var app = require('express')();

app.use('/proxy', proxy('www.google.com', {
  forwardPath: function(req, res) {
    return require('url').parse(req.url).path;
  }
}));

filter

The filter option can be used to limit what requests are proxied. For example, if you only want to proxy get request

app.use('/proxy', proxy('www.google.com', {
  filter: function(req, res) {
     return req.method == 'GET';
  },
  forwardPath: function(req, res) {
    return require('url').parse(req.url).path;
  }
}));

intercept

You can intercept the response before sending it back to the client.

app.use('/proxy', proxy('www.google.com', {
  intercept: function(rsp, data, req, res, callback) {
    // rsp - original response from the target
    data = JSON.parse(data.toString('utf8'));
    callback(null, JSON.stringify(data));
  }
}));

decorateRequest

You can change the request options before it is sent to the target.

app.use('/proxy', proxy('www.google.com', {
  decorateRequest: function(reqOpt, req) {
    reqOpt.headers['Content-Type'] = '';
    reqOpt.method = 'GET';
    reqOpt.bodyContent = wrap(req.bodyContent);
    return reqOpt;
  }
}));

preserveHostHdr

You can copy the host HTTP header to the proxied express server using the preserveHostHdr option.

app.use('/proxy', proxy('www.google.com', {
  preserveHostHdr: true
}));

reqBodyEncoding

Encoding used to decode request body. Default to utf-8.

Use null to avoid decoding and pass the body as is. Accept any values supported by raw-body.

app.use('/post', proxy('httpbin.org', {
  reqBodyEncoding: null
}));

timeout

By default, node does not express a timeout on connections. Use timeout option to impose a specific timeout. Timed-out requests will respond with 504 status code and a X-Timeout-Reason header.

app.use('/', proxy('httpbin.org', {
  timeout: 2000  // in milliseconds, two seconds
}));

Questions

Q: Can it support https proxy?

A: Yes, you can use the 'https-proxy-agent' package. Something like this:

var corporateProxyServer = process.env.HTTP_PROXY || process.env.http_proxy || process.env.HTTPS_PROXY || process.env.https_proxy;

if (corporateProxyServer) {
  corporateProxyAgent = new HttpsProxyAgent(corporateProxyServer);
}

Then inside the decorateRequest method, add the agent to the request:

  req.agent = corporateProxyAgent;

Release Notes

Release	Notes
0.7.4	Move jscs to devDependencies to avoid conflict with nsp.
0.7.3	Adds a timeout option. Code organization and small bug fixes.
0.7.2	Collecting many minor documentation and test improvements.
0.4.0	Signature of intercept callback changed from function(data, req, res, callback) to function(rsp, data, req, res, callback) where rsp is the original response from the target

Licence

MIT